Findings on low-field cranial MR images in epileptic dogs that lack interictal neurological deficits

Diagnostic utility of serum bile acids in dogs presenting with epileptic seizures consistent with a tier 1 confidence level diagnosis of idiopathic epilepsy

BACKGROUND

The International Veterinary Epilepsy Task Force consensus guidelines recommend performing fasting serum bile acid (SBA) and/or serum ammonia measurements as part of a tier 1 diagnosis of idiopathic epilepsy in dogs. The aim of this retrospective study was to determine the diagnostic utility of fasting SBA in this population.

METHODS

Dogs that met the tier 1 confidence level diagnosis of idiopathic epilepsy, with the additional requirement of both fasting and 2-hour postprandial SBA measurements, were included. The incidence of significant hepatopathies and usefulness of dynamic SBA testing and minimum database results were analysed.

RESULTS

A total of 233 dogs were included. All dogs diagnosed with clinically significant hepatopathy had elevations in postprandial SBA, with eight of 14 (57.14%) showing elevations in fasting SBA. The prevalence of clinically significant hepatopathies that could have been missed without using postprandial SBA measurement was 1.29%.

LIMITATIONS

The further investigations performed were not uniform and there were limitations in the ability to control sampling techniques due to the retrospective nature of this study. Investigations into hepatopathy were not standardised across this study population.

CONCLUSIONS

This study documents the importance of postprandial SBA measurements in the detection of hepatopathies and reveals that non-dynamic blood sampling has a negative predictive value of 91% for detecting elevated postprandial SBA, specific to dogs meeting the tier 1 confidence level diagnosis of idiopathic epilepsy.

[Diagnostics in epilepsy - potential of magnetic resonance imaging]

Epilepsy is a common neurologic disease frequently encountered by small animal practitioners. The disease comprises a multiplicity of clinical presentations and etiologies and often necessitates a comprehensive as well as cost-intensive diagnostic workup. This is mandatory in order to be able to diagnose or exclude a metabolic cause of the seizures and to distinguish between idiopathic and structural epilepsy. The examination by means of magnetic resonance imaging (MRI) represents a central component of the diagnostic workup, which in turn has essential effects on treatment and prognosis. In order to achieve standardized examination and comparable results, it is of utmost importance to use defined MRI protocols. Accordingly, communication and interaction between clinical institutions may be facilitated and as of yet undetected structural changes might be recorded in future MRI techniques. This review article sets particularly emphasis on the definition and classification of epilepsy as well as its diagnostic imaging procedures and refers to statistics and specialists' recommendations for the diagnostic workup in dogs.

Cerebrospinal fluid lactate concentrations in dogs with seizure disorders

BACKGROUND

Cerebrospinal fluid (CSF) lactate concentrations increase after seizure activity in many human patients independent of the underlying disease process. The effect of seizure activity on CSF lactate concentration in dogs is unknown.

HYPOTHESIS/OBJECTIVES

Cerebrospinal fluid lactate concentration is unaffected by seizure activity in dogs and is more dependent on the underlying disease process causing the seizures.

ANIMALS

One-hundred eighteen client-owned dogs with seizure disorders.

METHODS

Case series. Cerebrospinal fluid lactate concentration was determined using a commercially available lactate monitor. Seizure semiology, time from last seizure to CSF collection, number of seizures within the 72 hours preceding CSF collection, and clinical diagnosis were recorded.

RESULTS

Dogs with focal seizures had higher CSF lactate concentrations than did those with generalized seizures (P = .03). No differences in lactate concentrations were found among dogs with single seizures, cluster seizures or status epilepticus (P = .12), among dogs with CSF collection at different time points after the last seizure activity (P = .39) or among dogs having different numbers of seizures within the 72 hours preceding CSF collection (P = .42). A significant difference (P = .001) was found in CSF lactate concentrations among diagnostic groups, and dogs with inflammatory and neoplastic disease had higher concentrations than did dogs with idiopathic or unknown epilepsy.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cerebrospinal fluid lactate concentration is minimally affected by seizure activity in dogs and increased concentrations are more likely associated with the underlying disease process.

Analysis of Early Assessable Risk Factors for Poor Outcome in Dogs With Cluster Seizures and Status Epilepticus

Status epileptics (SE) and cluster seizures (CS) are serious neurological emergencies associated with poor outcome in epileptic patients. Data on risk factors associated with outcome in epileptic patients affected by CS and SE have not been studied extensively to date. In the present retrospective study potential risk factors predictive of negative outcome in a population of dogs affected by CS and SE were analyzed. Ninety-three dogs were included in the study: 21/93 patients (23%) presented with SE and 72/93 (77%) with CS. Based on multivariate statistical analysis, factors statistically associated with a poor outcome were the occurrence of the first epileptic seizure outside the defined idiopathic interval (6 months-6 years), a condition of hyperthermia at presentation and the absence of previous antiepileptic drugs (AEDs) in case of previous history of seizures. The results of the present study implement data on risk factors associated with poor outcome in dogs affected by CS or SE and can aid in the creation of an ad hoc scoring system, similar to systems currently applied in human medicine upon hospital admission to benchmark performances and establish protocols for triage and therapeutic management.

Epidemiology of recurrent seizure disorders and epilepsy in cats under primary veterinary care in the United Kingdom

Background

Little epidemiological evaluation of recurrent seizure disorders in cats currently exists in veterinary literature.

Objectives

To report the prevalence and risk factors for recurrent seizure disorders (RSD) and epilepsy in cats presented to primary care veterinary practices in the United Kingdom (UK).

Animals

A total of 285 547 cats under veterinary care during 2013 presenting to 282 primary care clinics in the UK.

Methods

Cohort study using multivariable logistic regression modeling for risk factor analysis.

Results

There were 458 confirmed RSD cases, giving a 1‐year period prevalence of 0.16% (95% confidence interval [CI], 0.15‐0.18). A subset of 114 (24.89%) cases was recorded as having epilepsy, giving a 1‐year period prevalence of 0.04% (95% CI, 0.03‐0.5). Increasing age was significantly associated with increasing odds of RSD. Breed, sex, neuter status, and body weight were not associated with RSD. Epilepsy was most frequently diagnosed in adult to middle‐aged cats. Cats aged 3.0 to <6.0 years had 3.32 times higher odds of epilepsy diagnosis compared to cats <3.0 years of age. Insured cats were more likely to be diagnosed with epilepsy compared to noninsured cats.

Conclusions and Clinical Importance

Although less common than in dogs, RSD and epilepsy still comprise an important disorder group in the UK cat population. Aging is a significant risk factor for these disorders in cats.

Estimation of the prevalence of idiopathic epilepsy and structural epilepsy in a general population of 900 dogs undergoing MRI for epileptic seizures

Due to variation in study designs the prevalence of idiopathic epilepsy (IE) and structural epilepsy (SE) in dogs is largely unknown. The objective was to provide estimates of the prevalence of IE and SE in a large population of dogs undergoing MRI for epileptic seizures. A retrospective study on 900 dogs undergoing MRI for seizures was performed. MRI scans, summary clinical history and neurological examination from the VetCT database were reviewed and a diagnosis assigned by board-certified radiologists. Structural lesions were identified as a cause of seizures in 45.1 per cent (n=406) of cases. No structural lesions were identified in 54.9 per cent (n=494) of cases with presumed IE diagnosed in 53.8 per cent (n=484) of dogs. Dogs between six months and six years were more often associated with IE (P<0.001), small breeds were overrepresented with suspected inflammatory brain disease (P=0.001) and large entire dogs more often diagnosed with extra-axial neoplasms (P=0.001). Over 31.0 per cent of dogs with suspected IE were six years or older. This study is the largest of its kind in dogs and provides accurate estimates of underlying causes of epilepsy. MRI findings should be considered in the context of a detailed clinical history and neurological examination.

Diagnostic value of cerebrospinal fluid analysis in a population of dogs with suspected idiopathic epilepsy

Cerebrospinal fluid (CSF) analysis is commonly used in the diagnostic investigation of seizure disorders in order to exclude possible inflammatory underlying aetiology. The medical records were searched for dogs presenting with epileptic seizures (ES) that had normal interictal neurological examination, normal complete blood count and biochemistry analysis, unremarkable MRI of the brain and had CSF analysis performed as part of the diagnostic investigation. A total of 200 dogs met the inclusion criteria. The CSF was abnormal in 30 dogs with a median total nucleated cell count of two cells/µl (IQR 1.5-6) and median protein concentration of 0.37 g/l (IQR 0.31-0.41). Pleocytosis was recorded in 14/30 dogs and the CSF protein was increased in 22/30. There was no correlation between abnormal CSF and the type or number of seizures or the time interval between the last seizure and CSF collection. A significant correlation was found between the number of red blood cells on CSF and having an abnormal CSF. The prevalence of having a diagnosis other than suspected idiopathic epilepsy (IE) was 0.5 per cent (1/200). These results suggest that performing CSF analysis in dogs with recurrent ES that have normal interictal neurological examination and unremarkable MRI has a low diagnostic value.

Consensus recommendations on standardized magnetic resonance imaging protocols for multicenter canine brain tumor clinical trials

The National Cancer Institute Comparative Brain Tumor Consortium, Patient Outcomes Working Group, propose a consensus document in support of standardized magnetic resonance imaging protocols for canine brain tumor clinical trials. The intent of this manuscript is to address the widely acknowledged need to ensure canine brain tumor imaging protocols are relevant and have sufficient equivalency to translate to human studies such that: (1) multi-institutional studies can be performed with minimal inter-institutional variation, and (2) imaging protocols are consistent with human consensus recommendations to permit reliable translation of imaging data to human clinical trials. Consensus recommendations include pre- and postcontrast three-dimensional T1-weighted images, T2-weighted turbo spin echo in all three planes, T2*-weighted gradient recalled echo, T2-weighted fluid attenuated inversion recovery, and diffusion weighted imaging/diffusion tensor imaging in transverse plane; field of view of ≤150 mm; slice thickness of ≤2 mm, matrix ≥ 256 for two-dimensional images, and 150 or 256 for three-dimensional images.

Canine versus human epilepsy: are we up to date?

In this paper we analyse and compare features of canine and human epilepsy and we suggest new tools for better future understanding of canine epilepsy. The prevalence of epileptic seizures in dogs ranges between 0.5% and 5.7% and between 1% and 3% in the human population. Studies on human epilepsy provide a ready-made format for classification, diagnosis and treatment in veterinary epilepsy. Human studies highlight the value of a thorough seizure classification. Nevertheless, a matter of concern in canine epilepsy is the limited information regarding seizure description and classification because of the lack of EEG-video recording. Establishment of a consensus protocol for ambulatory home video-recording in dogs who suffer from epilepsy, mainly considering indications, duration of monitoring, the sufficient essential training for an optimal interpretation of ictal semiology and the methodology of recordings is needed. The ultimate goal is that the information gathered by these videos will be analysed to describe the epileptic seizures thoroughly, recognize patterns and move towards a better understanding and therefore classification of canine epileptic seizures.

2015 ACVIM Small Animal Consensus Statement on Seizure Management in Dogs

This report represents a scientific and working clinical consensus statement on seizure management in dogs based on current literature and clinical expertise. The goal was to establish guidelines for a predetermined, concise, and logical sequential approach to chronic seizure management starting with seizure identification and diagnosis (not included in this report), reviewing decision‐making, treatment strategies, focusing on issues related to chronic antiepileptic drug treatment response and monitoring, and guidelines to enhance patient response and quality of life. Ultimately, we hope to provide a foundation for ongoing and future clinical epilepsy research in veterinary medicine.

Clinical Features in Border Terrier Dogs with Paroxysmal Involuntary Movements

Background

There have been anecdotal reports of episodic involuntary movements in the Border Terrier dog breed for over a decade. Recently, it has been hypothesized that this condition may be a form of paroxysmal dystonic choreoathetosis. The aim of this study was to characterize the phenomenology and clinical course of this condition and compare it to known human movement disorders.

Methods

Data were collected retrospectively from clinical cases treated by veterinary neurologists and additional information was collected prospectively with an ad-hoc online survey directed to owners of affected dogs.

Results

The episodes are characterized by generalized dystonia, tremors, titubation, and, in some cases, autonomic signs, such as salivation and vomiting. The median age at onset of the episodes was 3 years and the interval between clusters of episodes could last several months. Most of the episodes occurred from rest, and 67% of the owners reported that the episodes were associated with a trigger, most often excitement. Some owners reported an improvement after changing their dog's diet. We hypothesize that the Border Terrier attacks represent a form of paroxysmal nonkinesigenic dyskinesia.

Conclusions

The finding of a dystonia phenotype within an inbred population suggests a genetic predisposition, and elucidating the genetic cause could facilitate improved understanding of dystonia. This genetic predisposition and the effect of treatment with anticonvulsant drugs and dietary changes on the severity of the paroxysms warrant further investigation on this condition.

Epilepsy in dogs five years of age and older: 99 cases (2006-2011)

OBJECTIVE

To classify the etiology of epilepsy and evaluate use of abnormal neurologic examination findings to predict secondary epilepsy in dogs ≥ 5 years of age.

DESIGN

Retrospective case series.

ANIMALS

99 dogs with epilepsy.

PROCEDURES

Medical records were reviewed to identify client-owned dogs evaluated for seizures at ≥ 5 years of age with a diagnosis of primary or secondary epilepsy. Dogs were stratified by age; prevalence of primary and secondary epilepsy and the proportion of dogs with secondary epilepsy that had a diagnosis of neoplasia (on the basis of MRI findings) versus other disease were evaluated. Sensitivity and specificity of abnormal neurologic findings to detect secondary epilepsy were determined.

RESULTS

7 of 30 (23%) dogs 5 to 7 years of age, 13 of 29 (45%) dogs 8 to 10 years of age, 13 of 33 (39%) dogs 11 to 13 years of age, and 2 of 7 dogs ≥ 14 years of age had primary epilepsy. Prevalence of primary vs secondary epilepsy did not differ among age groups. The proportion of dogs with neoplasia at 5 to 7 years of age was lower than that of dogs in other age groups. Abnormal neurologic examination results had 74% sensitivity and 62% specificity to predict secondary epilepsy.

CONCLUSIONS AND CLINICAL RELEVANCE

A substantial proportion of dogs ≥ 5 years of age had primary epilepsy. Results indicated that lack of abnormalities on neurologic examination does not exclude the possibility of intracranial lesions, and MRI with CSF analysis (when applicable) should be recommended for all dogs with onset of seizures at ≥ 5 years of age.

Efficacy, safety, and tolerability of imepitoin in dogs with newly diagnosed epilepsy in a randomized controlled clinical study with long-term follow up

BACKGROUND

Imepitoin is a novel antiepileptic drug for the treatment of canine idiopathic epilepsy. The present study was conducted to demonstrate superior antiepileptic activity of a high dose of 30 mg/kg BID over a low dose of 1 mg/kg BID of imepitoin during 12 weeks of treatment under double blind conditions in a field population of dogs with previously untreated epilepsy. In a consecutive 12 weeks open label follow up (phase 2), all animals received 30 mg/kg BID, to evaluate the persistence of the antiepileptic activity, and to evaluate the effect of a dose step up to 30 mg/kg in the former low-dose animals.

RESULTS

A treatment with 30 mg/kg BID resulted in a significantly greater reduction in monthly seizure frequency relative to baseline data as compared to the 1 mg/kg dose. Both generalized and partial seizures but not cluster seizures were significantly less frequent in the high dose group. The antiepileptic activity was maintained during study phase 2 in the high dose group. An increase to 30 mg/kg BID in the low- dose animals resulted in a significant reduction in generalized and partial seizures, but not cluster seizures. At the end of study phase 2, 32.1 and 46.8 % of dogs of the former high and former low-dose groups respectively, remained free of generalized tonic-clonic seizures. Imepitoin was well tolerated. The frequency of dogs with any adverse drug reactions was higher in the 30 mg/kg BID dose (59 % vs. 41 %, p = 0.041), and the main target organ was the central nervous system (CNS). The occurrence of CNS related adverse reactions was transient and findings were mostly restricted to the first weeks of treatment. No hepatic enzyme increase and no other organ toxicity were observed.

CONCLUSION

The administration of imepitoin twice daily at a dose of 30 mg/kg results in significant and persistent antiepileptic effects in patients with newly diagnosed epilepsy and generalized tonic-clonic seizures, as observed over a study period of up to 6 months. Imepitoin was well tolerated. Most CNS related adverse drug reactions were transient. Both the antiepileptic activity and the safety profile make the drug suitable for long-term clinical use.

International Veterinary Epilepsy Task Force recommendations for a veterinary epilepsy-specific MRI protocol

Epilepsy is one of the most common chronic neurological diseases in veterinary practice. Magnetic resonance imaging (MRI) is regarded as an important diagnostic test to reach the diagnosis of idiopathic epilepsy. However, given that the diagnosis requires the exclusion of other differentials for seizures, the parameters for MRI examination should allow the detection of subtle lesions which may not be obvious with existing techniques. In addition, there are several differentials for idiopathic epilepsy in humans, for example some focal cortical dysplasias, which may only apparent with special sequences, imaging planes and/or particular techniques used in performing the MRI scan. As a result, there is a need to standardize MRI examination in veterinary patients with techniques that reliably diagnose subtle lesions, identify post-seizure changes, and which will allow for future identification of underlying causes of seizures not yet apparent in the veterinary literature.

There is a need for a standardized veterinary epilepsy-specific MRI protocol which will facilitate more detailed examination of areas susceptible to generating and perpetuating seizures, is cost efficient, simple to perform and can be adapted for both low and high field scanners. Standardisation of imaging will improve clinical communication and uniformity of case definition between research studies. A 6–7 sequence epilepsy-specific MRI protocol for veterinary patients is proposed and further advanced MR and functional imaging is reviewed.

International veterinary epilepsy task force consensus proposal: diagnostic approach to epilepsy in dogs

This article outlines the consensus proposal on diagnosis of epilepsy in dogs by the International Veterinary Epilepsy Task Force. The aim of this consensus proposal is to improve consistency in the diagnosis of epilepsy in the clinical and research settings. The diagnostic approach to the patient presenting with a history of suspected epileptic seizures incorporates two fundamental steps: to establish if the events the animal is demonstrating truly represent epileptic seizures and if so, to identify their underlying cause. Differentiation of epileptic seizures from other non-epileptic episodic paroxysmal events can be challenging. Criteria that can be used to make this differentiation are presented in detail and discussed. Criteria for the diagnosis of idiopathic epilepsy (IE) are described in a three-tier system. Tier I confidence level for the diagnosis of IE is based on a history of two or more unprovoked epileptic seizures occurring at least 24 h apart, age at epileptic seizure onset of between six months and six years, unremarkable inter-ictal physical and neurological examination, and no significant abnormalities on minimum data base blood tests and urinalysis. Tier II confidence level for the diagnosis of IE is based on the factors listed in tier I and unremarkable fasting and post-prandial bile acids, magnetic resonance imaging (MRI) of the brain (based on an epilepsy-specific brain MRI protocol) and cerebrospinal fluid (CSF) analysis. Tier III confidence level for the diagnosis of IE is based on the factors listed in tier I and II and identification of electroencephalographic abnormalities characteristic for seizure disorders. The authors recommend performing MRI of the brain and routine CSF analysis, after exclusion of reactive seizures, in dogs with age at epileptic seizure onset <6 months or >6 years, inter-ictal neurological abnormalities consistent with intracranial neurolocalisation, status epilepticus or cluster seizure at epileptic seizure onset, or a previous presumptive diagnosis of IE and drug-resistance with a single antiepileptic drug titrated to the highest tolerable dose.

This consensus article represents the basis for a more standardised diagnostic approach to the seizure patient. These recommendations will evolve over time with advances in neuroimaging, electroencephalography, and molecular genetics of canine epilepsy.

Treatment in canine epilepsy--a systematic review

Background

Various antiepileptic drugs (AEDs) are used for the management of canine idiopathic epilepsy (IE). Information on their clinical efficacy remains limited. A systematic review was designed to evaluate existing evidence for the effectiveness of AEDs for presumptive canine IE. Electronic searches of PubMed and CAB Direct were carried out without date or language restrictions. Conference proceedings were also searched. Peer-reviewed full-length studies describing objectively the efficacy of AEDs in dogs with IE were included. Studies were allocated in two groups, i.e. blinded randomized clinical trials (bRCTs), non-blinded randomized clinical trials (nbRCTs) and non-randomized clinical trials (NRCTs) (group A) and uncontrolled clinical trials (UCTs) and case series (group B). Individual studies were evaluated based on the quality of evidence (study design, study group sizes, subject enrolment quality and overall risk of bias) and the outcome measures reported (in particular the proportion of dogs with ≥50% reduction in seizure frequency).

Results

Twenty-six studies, including two conference proceedings, reporting clinical outcomes of AEDs used for management of IE were identified. Heterogeneity of study designs and outcome measures made meta-analysis inappropriate. Only four bRCTs were identified in group A and were considered to offer higher quality of evidence among the studies. A good level of evidence supported the efficacy of oral phenobarbital and imepitoin and fair level of evidence supported the efficacy of oral potassium bromide and levetiracetam. For the remaining AEDs, favorable results were reported regarding their efficacy, but there was insufficient evidence to support their use due to lack of bRCTs.

Conclusions

Oral phenobarbital and imepitoin in particular, as well as potassium bromide and levetiracetam are likely to be effective for the treatment of IE. However, variations in baseline characteristics of the dogs involved, significant differences between study designs and several potential sources of bias preclude definitive recommendations. There is a need for greater numbers of adequately sized bRCTs evaluating the efficacy of AEDs for IE.

Risk factors for survival in a university hospital population of dogs with epilepsy

BACKGROUND

Although a common neurological disorder in dogs, long-term outcome of epilepsy is sparsely documented.

OBJECTIVES

To investigate risk factors for survival and duration of survival in a population of dogs with idiopathic epilepsy or epilepsy associated with a known intracranial cause.

ANIMALS

One hundred and two client owned dogs; 78 dogs with idiopathic epilepsy and 24 dogs with epilepsy associated with a known intracranial cause.

METHODS

A retrospective hospital based study with follow-up. Dogs diagnosed with epilepsy between 2002 and 2008 were enrolled in the study. Owners were interviewed by telephone using a structured questionnaire addressing epilepsy status, treatment, death/alive, and cause of death.

RESULTS

Median life span was 7.6 years, 9.2 years, and 5.8 years for all dogs, and dogs with idiopathic epilepsy or dogs with epilepsy associated with a known intracranial cause (P < .001), respectively. Survival time for dogs with idiopathic epilepsy was significantly (P = .0030) decreased for dogs euthanized because of epilepsy (median: 35 months) compared to dogs euthanized for other reasons (median: 67.5 months). Neutered male dogs with idiopathic epilepsy had a significant (P = .031) shorter survival (median: 38.5 months) after index seizure compared to intact male dogs (median: 71 months). Treatment with two antiepileptic drugs (AED's) did not negatively influence survival (P = .056).

CONCLUSION AND CLINICAL IMPORTANCE

Dogs with idiopathic epilepsy can in many cases expect a life span close to what is reported for dogs in general. In dogs where mono-therapy is not sufficient, the need for treatment with two AED's is not linked to a poor prognosis.

Canine epilepsy as a translational model?

Dogs with spontaneous diseases can exhibit a striking similarity in etiology, clinical manifestation, and disease course when compared to human patients. Therefore, dogs are intensely discussed as a translational model of human disease. In particular, genetic studies in selected dog breeds serve as an excellent tool to identify epilepsy disease genes. In addition, canine epilepsy is discussed as a translational platform for drug testing. On one hand, epileptic dogs might serve as an interesting model by allowing the evaluation of drug efficacy and potency under clinical conditions with a focus on chronic seizures resistant to standard medication, preventive strategies, or status epilepticus. On the other hand, several limitations need to be considered including owner-based seizure monitoring, species differences in pharmacokinetics and drug interactions, as well as cost-intensiveness. The review gives an overview on the current state of knowledge regarding the etiology, clinical manifestation, pathology, and drug response of canine epilepsy, also pointing out the urgent need for further research on specific aspects. Moreover, the putative advantages, the disadvantages, and limitations of antiepileptic drug testing in canine epilepsy are critically discussed.

Prevalence and risk factors for canine epilepsy of unknown origin in the UK

Epidemiological evaluation of canine epilepsy is an under-researched area. The objectives of this study were to estimate prevalence and investigate risk factors for epilepsy of unknown origin (EUO) among dogs attending primary veterinary practices in the UK. The clinical data analysed spanned a two-year period and included all dogs attending 92 primary veterinary clinics participating in the VetCompass project. Five hundred and thirty-nine EUO cases were identified giving a prevalence of 0.62% (95% CI 0.57% to 0.67%). Males were over 1.5 times as likely to have EUO compared with females (95% CI 1.44 to 2.06; P < 0.001). Of purebred dogs, the border terrier had 2.70 (95% CI 1.57 to 4.62; P < 0.001) and the German shepherd dog had 1.90 (95% CI 1.28 to 2.80; P=0.001) times increased odds of EUO compared with crossbred dogs. In addition, the West Highland white terrier had reduced odds (OR 0.23; 95% CI 0.08 to 0.62; P=0.004) of EUO compared with crossbred dogs (likelihood ratio test P < 0.0001). No association was found with neuter status, colour or weight. The current study highlights the clinical importance of epilepsy as a canine disorder in the UK. Increased awareness of sex and breed predispositions may assist clinicians with diagnosis. Further research is merited to evaluate the specific breed associations identified.

Epilepsy in Border Collies: clinical manifestation, outcome, and mode of inheritance

BACKGROUND

There is a lack of data on idiopathic epilepsy (IE) in Border Collies (BCs) in the veterinary literature.

HYPOTHESIS

Genetic epilepsy occurs in BCs and is frequently characterized by a severe clinical course and poor response to medical treatment.

ANIMALS

Forty-nine BCs diagnosed with IE.

METHODS

Medical records, seizure data, treatment data, and pedigree information of affected dogs were collected. Cases were classified phenotypically as affected or not affected; mild, moderate, or severe clinical course; active epilepsy (AE) or remission; and drug resistant or not drug resistant.

RESULTS

Clinical manifestations were classified as having a moderate (33%) or severe clinical course (49%), characterized by a high prevalence of cluster seizures and status epilepticus. Survival time was significantly decreased in dogs < 2 years of age at seizure onset, and in dogs with a severe clinical course. Drug resistance was apparent in 71% of 24 dogs treated with > 2 antiepileptic drugs. The epilepsy remission rate was 18%. Median age at onset was significantly higher and initial seizure frequency was significantly lower in dogs with remission compared with dogs with AE. Pedigree analyses indicated a strong genetic founder effect in the appearance of epilepsy, resembling autosomal recessive inheritance.

CONCLUSION AND CLINICAL IMPORTANCE

The present study confirms the occurrence of genetically mediated epilepsy with a frequent severe clinical course and drug resistance in BCs. The results provide information about the long-term prognosis of IE in BCs for veterinarians and concerned owners, and may benefit breeders as well.